Botox is often used to treat a gummy smile by relaxing the muscles that pull the lip upwards when smiling. This must be done carefully to avoid a droopy upper lip, and if done excessively or incorrectly it can result in a long flat lip appearance. If the lip lengthens too much it will typically only last a short period of time and then improve. Best regards
For the treatment of the gummy smile, the upper lip does not raise as high so the upper lip may appear to be a little longer. The rest of the lip shape does not change.